Fluid dynamic control device



NOV- 1, 1966 H. H. UNFRIED 3,282,051

FLUID DYNAMIC CONTROL DEVICE Filed Feb. 4, 1965 4 Sheets-Sheet 1 INVENTOR.

Nov. 1, 1966 H. H. UNFRIED FLUID DYNAMIC CONTROL DEVICE 4 Sheets-Sheet 2 Filed Feb. 4, 1965 lla! Nov. 1, 1966 H. H. UNFRu-:D 3,282,051

FLUID DYNAMIC CONTROL DEVICE Filed Feb. 4, 1965 4 Sheets-Sheet /af/ 457C Nov. l, 1966 H. H. uNFRu-:D

FLUID DYNAMIC CONTROL DEVICE 4 Sheets-Sheet 4 Filed Feb. 4, 1965 United States Patent Olice Patented Nov. 1, 1966 3,282,051 FLUID DYNAMIC CONTRGL DEVICE Happy Hugh Unfried, Los Angeles, Calif., assigner to Mattel, Inc., Hawthorne, Calif., a corporation of California Filed Feb. 4, 196s, ser. No. 430,427 44 Claims. (Cl. 60230) The present invention relates to a lluid dynamic control device, and 'more particularly to an acoustically activated uid dynamic control device which may be used as a thrust vectoring device or to control the operation of electrical and mechanical devices.

Although prior art fluid dynamic control devices are known, they do have certain disadvantages.

A Imajor disadvantage resides in the fact that the fluid jet employed in such prior art devices is comparatively stable to small disturbances, hence, the devices are relatively insensitive to low amplitude sound waves.

Another disadvantage resides in the fact that certain of these `prior art Adevices do not lend themselves readily to controlling devices having more than a single operating mode.

A further disadvantage resides in the fact that they do not lend themselves readily to adjustment to compensate for changes in operating modes or parameters.

Yet another disadvantage resides in the fact that they require a secondary input having a net mass flow in the form of a i'luid control stream.

In View of the foregoing factors and conditions characteristic of fluid dynamic control devices, it is a primary object of the present invention to provide a new and useful iiuid dynamic control device not subject to the disadvantages enumerated above and having means for operating a fluid jet in the region of ow where it is rnost unstable to small disturbances so that it is sensitive to sound waves.

Another obje-ct to the present invention is to provide a device of the type described which includes means to augment the acoustic particle velocity in the vicinity of the jet orice.

Yet another object of the present invention is to provide a device of the type described which includes an acoustic resonator having a resonant frequency corresponding to the `characteristic frequency to which the fluid jet employed in the device is most sensitive.

A further object of the present invention is to provide a device of the type described having a nozzle exit including boundaries which are adjusted so that the jet is, in the undisturbed state, normally lmonostable on one boundary, and in the disturbed state, is conditionally stable on the opposite boundary.

A further object of the present invention is to provide a device of the type described which includes means to adjust its monostable operating point.

A still further object of the present invention is to provide an acoustically controlled thrust vectoring device.

Another object of the present invention is to provide a new and useful acoustically activated fluid dynamic control device which may be used to control the operation of electrical and mechanical devices.

Another object of the present invention is to provide a device of the type described which does not require a secondary input which has a net mass ilow in the form of a fluid control stream.

According to the present invention, several embodirnents of an acoustically activated fluid dynamic control device are provided which employ the general principle that the stable operating position of a uid jet as it issues from an oriice in the presence of suitable boundaries can be changed by disturbing it acoustically.

The several embodiments of the device include means for operating a uid jet in the region of flow where it is most unstable to small disturbances; hence, it is sensitive to sound `waves with the appropriate orientation.

Although the stream flow direction can `be altered by simply usinga strong disturbing sound, it is preferable to increase the sensitivity of the device by incorporating an acoustic resonator into the device. The acoustic resonator augments the acoustic particle velocity in the vicinity of the jet orifice, and increases the frequency selectivity of the device. The resonant frequency of the resonator corresponds to the characteristic frequency at which the jet is most sensitive to small disturbances.

In addition, means are provided for controlling the boundary layer of the jet for improved directional control. The nozzle or orice exit -boundaries of the device are adjusted so that the jet is, in the undisturbed state, normally monostable on one boundary, and in the disturbed state, it is conditionally stable on the opposite boundary.

In addition, one embodiment includes a tluid biasing leak which is employed to control the stability of the fluid stream operating in its irnonostable region.

In yet another embodiment, a central uid supply is employed to operate two or more control devices in the region of maximum instability, and such separate control devices can be operated simultaneously at different frequencies.

In a further embodiment of the present invention, a greater momentum of flow than can be co-ntrolled acoustically, such as a thrust producing jet for a vehicle, is held oi a nozzle boundary by an acoustically controlled jet in the undisturbed stable state. When acoustically disturbed, the control jet switches -positions and the power jet becornes attached to the nozzle boundary in such a manner that the device operates as a thrust vectoring device.

Another embodiment includes vane means which is actuated by t-he disturbed jet so that it is caused to rock about its pivot and perform useful work and in yet another embodiment, the curtain jet of a ground effect vehicle is altered acoustically. In all embodiments of the invention a fluid jet is acoustically controlled to, in turn, serve as a thrust vectoring device or to control other fluid iiows, or electrical or mechanical devices and processes without using a secondary input which has a net mass ilow in the form of a fluid control stream.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings in which like reference characters refer to like elements in the several views.

In the drawings:

FIGURE l is a perspective View of a first embodiment of an acoustically activated uid dynamic control device of the present invention;

FIGURES 2, 3 and 4 are partial plan views, on an enlarged scale, of the device of FIGURE 1 showing somewhat diagrammatically .the operation thereof;

FIGURE 5 is a plan view similar to FIGURE 3 showing a modication to the device of FIGURE l;

FIGURE 6 is a perspective view of a second embodiment of an acoustically activated fluid dynamic control device of the present invention;

FIGURE 7 is a perspective view of yet another form of the present invention;

FIGURE 8 is a plan View of a thrust vectoring device constituting a fourth embodiment of the present invention;

FIGURE 9 is a plan view of another embodiment of the present invention;

FIGURE 10 is a transverse, cross-sectional View, with parts shown in elevation, of a fifth embodiment of the present invention;

FIGURE 11 is a cross-sectional view taken along line 11-11 of FIGURE 10;

FIGURE 12 is a plan view showing somewhat diagrammatically a sixth embodiment of the present invention;

FIGURE 13 is a cross-sectional View of a seventh embodiment of the present invention;

FIGURES 14 land 15 are plan views showing somewhat diagrammatically the application `of the principles of the present invention to thrust vectoring and ight control;

FIGURE 16 is a perspective view of a ground eifects vehicle of the present invention; and

FIGURE 17 is an enlarged cross-sectional view taken along line 17-17 of FIGURE 16.

Referring again to the drawings and particularly to FIGURES 1-4 an acoustically activated fluid dynamic control device constituting a first embodiment of the present invention, generally designated 10, includes la first plate 12 (shown in phantom for clarity) and a second plate 14, forming suitable housing means.

A fluid storage and dispensing member 16 is rigidly mounted in the housing means formed by the plates 12 and 14 and is adapted to receive a suitable fluid, such as air under pressure from a blower 18 through a fluid inlet conduit 20. Other fluids, such as Water, can be employed. The relationships of jet velocity, jet thickness and frequency, for the same geometry of boundary layers, Will of course vary with changes in the viscosity of the fluid employed; but the invention defined herein is equally applicable to al1 practical fluids. The member I6 includes an accumulator chamber 22 which communicates with the conduit 2d through a suitable litting 24. Fluid accumulating in the chamber 22 is exhausted therefrom through a passageway or channel 26 having parallel or nearly parallel, spaced sidewalls 28 and 30 terminating in a channel exit or orice 32 provided in one end 34 of member 16. The passageway or channel 26 is preferably of sufficient length to insure that a laminar liow is imparted to the uid leaving chamber 22 before it reaches the channel exit or orice 32. Although a number `of different dimensions for the member 16 will manifest themselves, it has been found satisfactory to make the depth of the channel 26 approximately ten times its width and to make its length approximately times its width. Thus, the channel 26 and orifice 32 should produce a plane jet and not a round jet with the preferred aspect ratio `of the jet having a ratio greater than 5 to 1.

Suitable means, such as a nozzle block or boundary 38, is mounted between the plates 12 and 14 adjacent the end 34 of member 16. The block 38 is spaced a suitable distance downstream of the channel exit 32 by any suitable means, such as a shim 40. The block 33 also includes a portion 42 which lies laterally adjacent a jet or stream 43 issuing from the channel exit 32. The block 38` also includes a flat, `oblique face 44 which extends the laterally adjacent portion 42 and connects it to a downstream portion 46. The shim il may be made somewhat shorter .than the block 3S or other suitable means (not shown) may be used, to form a separating means, chamber 48, between the portion 42 of the block 38 and the end 3d of the member 16.

A second boundary means or nozzle block Si? is mounted -between plates 12 and 14 downstream of the channel exit 32. This second nozzle block Sli also includes a portion 52 which lies laterally adjacent the fluid stream 43 issuing from the channel exit 32 and which is joined by a llat face 54 to a downstream portion 56. The laterally adjacent portion 52 also lies slightly downstream of the corresponding portion 42 on the block 38. The block Si) is formed integrally with an elongated 4 member 58 which is preferably slidably mounted between corresponding edges of the plates 12 and 14 in spaced relation with the member 16 so that a chamber or resonator 6b is formed therebetween. The size of the chamber 6@ may `be controlled by a slidable block 62 which is reciprocally mounted between the member 16 and the member 56 and which includes a concaved end 64 forming an endwall for the chamber 6d. The chamber 6@ is in fluid communication with the channel exit 32 through a throat or neck member 66 which is formed by the portion 52 of block 5d and an oblique, flat face 68 provided on end 34 of the member I6.

The chamber 60 and the throat 66 form a suitable resonant means, such as an acoustic resonator of the Helmholtz type, which may be tuned to a predetermined frequency by shifting the member 62. Of course, it will be apparent to those skilled in the art that a resonant tube or diaphragm may be substituted for the acoustic resonator means herein shown and described, if desired. If should also be noted that the resonator can be eliminated if it is desired to employ a higher amplitude sound disturbance for the control. Preferably, however, a resonator is used so that a disturbing sound of small magnitude will be effective to operate the device in a manner to be hereinafter described.

The nozzle exit boundaries 3S and 50 are preferably adjusted so that the jet or stream issuing from. the channel exit 32. in the undisturbed state is normally monostable on the boundary 38 and in the disturbed state is conditionally stable on the opposite boundary 50. On the other hand, if the secondary boundary 50 is very nearly as close to the channel exit 32 and the direction of flow of the stream 43 as the boundary 38-i.e., if the adjustment of the device l@ is very finethe switching will be irreversible.

The jet 43 issuing from channel exit 32 is operated in the region of flow where it is most unstable to small disturbances; hence the jet is sensitive to sound waves which have the appropriate orientation and frequency.

The acoustic resonator chamber 60 is employed to increase the frequency selectivity of the device Il) beyond that which is obtainable by merely operating a jet in its free state in the region of flow where it is most unstable to small disturbances. The resonator augments the acoustic particle velocity in t-he vicinity of the orifice 32. The resonator chamber 6) is tuned to a frequency which corresponds to the characteristic frequency to which the jet 43 issuing from channel exit 32 is most sensitive.

The device 10 may be made from any suitable material such as metal, synthetic resin, plastic or the like. Preferably, the walls of the chamber 6l) are rigid and not compliant because the selectivity of the device 10 decreases as the compliance of the walls of chamber 60 increases.

In use, a suitable fluid under pressure, such as air or water, is supplied by the blower I8 to the accumulator 22 through conduit 2l). Fluid from the accumulator 22 then flows through the channel 26 attaining a laminar iiow before reaching the channel exit 32. Since this laminar flow issues from the channel exit 32 into a stagnant medium represented by the ambient atmosphere existing in the region 7@ between the blocks 38 and 5d, the jet or stream 43 will attach itself to the laterally adjacent portion 42 of block 3S and remain attached to the block 3S along the face ld between the portions 42 and d6. The manner in which the stream 43 becomes attached to the boundary 44 is accomplished as follows:

The stream initially issues from the orifice 32 and enters the stagnant medium at 70. Due to viscous drag, the fluid along the boundaries of the stream is entrained and carried along with the stream. Thus, a secondary ow is established on both sides of the free stream. Portion i2 is suiciently close to the boundary of the free stream so that the secondary llow from 7l) cannot enter the separating means or small chamber 4S to replenish the fluid which was entrained and exhausted. Therefore, the pressure in chamber- 4S is reduced below the pressure in the throat 66 `and the stagnant area 70 so that the resulting pressure gradient across the stream deflects it toward portion 42. This same sequence of events is repeated until the stream is fully attached to the boundary 44.

As long as the jet or stream 43 remains in the laminar state, it will remain `attached to boundary 44. Boundary S4 is sufficiently spaced from the channel exit 32 and the center line of the jet so that, if the jet were manually placed along the boundary 54, it would return to its stable state along the boundary 44. Thus, the stream in its undisturbed state is monostable. However, it is just barely in the monostable state and very close to the region of flow where it would become bistable.

The acoustic resonator means is tuned to the frequency at which it is desired to switch the jet or stream 43. When the chamber or resonator 60 is excited at resonance, the acoustic particle motion in the neck 66 interacts with the stream issuing from the channel exit 32 and produces undulations in the distribution of the vorticity of the stream. These undulations are basically unstable and as they are convected downstream they grow into sizeable vortices. The chamber 60 is excited at resonance by a suitable disturbance which drives resonator 6@ at resonance and which may comprise a suitable vibratory flow in a fluid, such as the sound illustrated diagrammatically at 72 in FIGURES 3 and 4. As the sound 72 disturbs the jet, a well developed vortex flow is produced which increases the entrainment on both sides of the stream 43, but predominantly on the side of the jet 4-3 adjacent throat 66, as shown by arrows '73 in FIGURE 2.

The pressure in the chamber 48 is further reduced and the jet 43 bends into the chamber 48 slightly, as shown in FIGURE 3 at 43a. Then the vigorous vortex flow past the portion 42 plus the increased centrifugal force of the jet 43 in the region of the portion 42 cause flow separation (43b, FIGURE 3) to ensue lalong boundary 44 freeing the jet 43 therefrom. Simultaneously, the increased entrainment in the region of the throat 65 (arrows 73a in FIGURE 3) resulting from the well developed vortex flow and the effective increase in t-'ne stream width tend to reduce the secondary flow entering region 66 from the atmosphere at 70. This allows the pressure gradient from region 70 to throat 66 to bend the jet 43 down to portion 52 of boundary 50 (as at 43C in FIGURE 4) until the flow attaches to the face 54 (as the vortex flow develops and is convected downstream, it reduces the available passage for the secondary flow from region 70 to throat 66; therefore, the pressure regenerative Coanda Effect comin-ences and the stream switches to face 54 of boundary 50). The stream remains attached to face 54 as long as the periodic, acoustic disturbance continues. When the disturbance ceases, by terminating sound T2, the jet 43 yagain assumes a laminar fiow and returns to its monostable state along the face 44 of boundary 38.

As is wel] known, the transition from laminar to turbulent fiow is an in-herent characteristic of boundary layer and free jet fluid flows as the Reynolds number increases. The magnitude of turbulence at any location can be considered to be an amplification of a disturbance which previously occurred upstream and which is the internal noise level of a free jet not externally excited. The phenomenon which makes the transition from the laminar flow to turbulent flow possible is employed in the device I0, but is controlled in such a manner that a well developed, periodic vortex flow takes place instead of a turbulent flow.

An acoustic disturbance created `by the sound 72 transforms a vortex sheet comprised of microscopic eddies into a vortex flow where the little eddies comprise a macroscopic vortex. However, the jet 43 is not unstable to disturbances of all frequencies so that the problem connected with shock and vibration being transmitted to the stream 43 at the channel exit 32 is minimized. The region where the jet 43 is most unstable corresponds to the case Where the ratio of jet thickness at the channel exit 32 to the flow wave length is from about 0.1 to 1.0. In actual practice, a ratio of between 0.2 and 0.4 has been found to be satisfactory. As hereinbefore noted, the resonator 60 can be eliminated by employing a very strong disturbing sound.

The jet or stream 43 may be employed to produce work by exerting a force against a suitable medium such -as the surrounding atmosphere, an electrical contact, a mechanical device or other fluid jets or by the mass displacement of the material being forced out by the jet. Thus, it is apparent that the device 10 can be employed to acoustically control the direction along which a jet stream can be caused to travel to exert a force in the form of work.

The device shown in FIGURES 1-4 is shown in modified form in FIGURE 5 as comprising a control device 10a which is substantially similar to the device 10 except that a thicker shim 40o is positioned between the end 34 and the nozzle block 38 to maintain it further down stream of the channel exit 32. This creates a larger chamber 48a.

In addition, the nozzle block S0 and its integral leg 5d have been repositioned 0n plate 14 in such a manner that the portion S2 of block 50 is Ipositioned nearer to the channel exit 32 than in the FIGURE l embodiment. Thus, the portion 52 in the FIGURE 5 embodiment lies upstream of the portion 42 instead of lying downstream thereof, as was the case in the FIGURE 1 embodiment. With this configuration, the jet stream 43 attaches to the boundary 54 in its undisturbed condition and becomes attached to the boundary 44 when it is acoustically disturbed. In practice, it has been found that the FIGURE l embodiment and the FIGURE 5 embodiment have approximately the same sensitivity although the FIGURE 5 embodiment is somewhat more difficult to control over larger ranges of stream velocity due to its greater susceptibilty to oscillation. The FIGURE 5 embodiment offers a geometry of the nozzle which allows a more effective ma-nner of distributing the stream 43, but this asset is balanced by the result that the acoustic resonance is more highly damped for this nozzle geometry as compared to the FIGURE 1 embodiment.

Referring now to FIGURE 6, a third embodiment of the present invention, generally designated 10b, includes a base :plate 14 and a cover plate f2 between which an integral accumulator, nozzle and resonator assembly 1Gb is mounted. The assembly feb includes an accumulator 22b which may be filled with a suitable fluid under pressure, such as air or water, through a fluid inlet 20. A channel Zeb places the accumulator 2217 in fluid communication with the channel exit 32h. The channel Zeb is designed to assure that the flow of fluid from accumulator 22h becomes laminar before it reaches the channel exit 32h and the channel 26!) preferably has a width to breadth ratio greater than 5 to l.

The member 16.5 also includes a first resonator chamber 661') and a separating means in the form of a second resonator chamber dill?. A first nozzle block Sdb is mounted between plates 12 and 14 across the end 34,5 of member 16h. The block 3811 defines boundary means having a portion 42h laterally adjacent a jet 43 issuing from the nozzle 32h. The block 3819 also includes an oblique face 44h.

A second nozzle block 50h is mounted between plates 12 and I4 across the end 34h and the resonator chamber 60h. The block SOI; includes a portion 5211 and an oblique face 54h. The portion 521; of block 50 lies further downstream than the portion 42h of block 38h so that the fow 43, in its undisturbed condition, will become attached to the face 44b. Then when the flow 43 is acoustically disturbed, it becomes attached to the face 54 of block 50h,

and when the disturbance is ceased the stream d3 returns to its initial position along face 4412.

In the FIGURE 6 embodiment, a pair of resonators otib and @1b are employed so that the stream 43 can be switched at two different sound frequencies 72 and 72b, respectively.

A fourth embodiment of the present invention, generally designated 10c, is shown in FIGURE 7 as including a housing assembly 8@ having end walls 81 and sidewalls 81a. A blower S2 is mounted in housing Sil and is powered by an electric motor Sd. The blower 82 supplies air under pressure to the channel exit 32e througs a passageway 26C.

A first nozzle block 33C is also mounted in housing 30 defining a boundary 44C having a portion 42C laterally adjacent the channel exit 32C. The nozzle block 38C includes a recessed portion 48C forming a separating means or chamber which corresponds to and performs the same function as the chamber 4S in the FIGURE l embodiment. A second nozzle block 50c forms a boundary 5de having a portion 52C laterally adjacent the channel exit 32e somewhat downstream of the corresponding portion 42C on nozzle block 380. A resonator chamber 60C is provided in housing St) and includes a throat 66e which is in fluid communication with channel exit 32C and chamber 48C.

A vane means 86 is rockably mounted on housing Si) by a pin 88 and includes a cupped portion 9@ extending over the boundary 44C in the path of ilow of a stream 43 issuing from channel exit 32e. The vane means 86 also includes a pair of counterweights 92 which statically balance the vane means 86. A spring 93 biases the cupped portion 9d toward nozzle block 38C to return the vane means S6 to its normal position when the stream 43 is not present.

When blower 82 is energized, the flow of tluid from the channel exit 32e attaches to the bound-ary 44e and iows into engagement with the cupped portion or member 9d creating suicient force to rock the vane means 86 about pivot 88 in a clockwise direction.

When a suitable sound, indicated diagrammatically at 72, drives the chamber 6de at resonance, the sound disturbs the stream issuing from channel exit 32e and causes it to become attached to the boundary 43C so that the stream no longer engages cupped member 90. The vane means Se will rotate in a counter clockwise direction bringing an electrical contact 9d carried thereby into engagement with an yelectrical contact 96. The electrical contacts 94 and 96 may be connected in a suitable electric circuit through leads 98 and 1%, respectively, to a device not shown, to be controlled by the device 10c.

Of course, it is obvious that the vane means do may be provided with a number of diterent types of mechanical linkages for use in controlling the operation of mechanical devices. The vane means S5 and the electrical contacts 94 and 96 may be covered by a suitable cover member, such as the one shown in phantom lines at 16M. Since the sound from blower 82 could disturb stream 43, a suitable iilter is provided in .the device 10c to attenuate the blower sound in a frequency band near the resonant frequency of chamber 6590. The filter comprises a chamber 105 and a neck 105. The neck 1% shunts the blower sound from channel 26C into chamber 1&5 where it is absorbed. The chamber 165 may be lled with a `suitable sound absorbing material or it may be left empty.

The embodiment of the present invention which is shown lin FIGURE 8 constitutes a thrust vectoring device ltld which includes an accumulator 22d which is mounted between plates 12d and 14d and which cornmunicates `through a passageway 25d with first channel exit 32d, a small chamber 48d and the throat odd of a resonator 60d. The device 16d also includes a first nozzle block 38d forming a -boundary 44d having a portion 42d laterally adjacent a control jet stream 43d which issues from the nozzle 32d when the accumulator 22d is pressurized. A second nozzle block Sd is also mounted downstream of the channel eXit 32d forming a boundary 54d having a portion 52d laterally 'adjacent the control jet strea-m 43d.

A third nozzle block or wedge 11@ is also provided downstream of the channel eXit 32d and includes a boundary 112 having 1a portion 114 later-ally adjacent a power jet 116 supplied through a passageway 117 by a suitable power source indicated diagrammatically tat 113. A conduit 12@ connects the source 118 with the accumulator 22d for supplying fluid under pressure thereto. The power jet 116 discharges through a second channel exit 119 provided at the end of passageway 117 to impart thrust to a vehicle being powered by the device 10d.

The power jet 116 is held off the boundary 112 by the control jet 43d when in the undisturbed stable state. When acoustically disturbed by means which will drive the resonant chamber 60d at resonance, such as a sound indicated diagrammatically at 72d, the control jet 43d switches positions and becomes attached to the boundary 54d. The power jet 116 then becomes attached to the boundary 112 changing the direction of thrust produced by the power jet 116. When incorporated into a toy, a vehicle or other suitable device, not shown, the thrust vectoring device 16d m-ay be employed as a remote control device to acoustically control the direction of movement thereof. In addition, either the power jet 11e or the control jet 43d, or both can be employed to perform work on a vane means of the type disclosed in FIGURE 7 or the like.

Referring now to FIGURE 9, a sixth embodiment of the present invention, generally designated 16e, includes plates 12e and 14e between which a member 16e is mounted. The member 16e includes an accumulator 22e to which a suitable fluid under pressure may be supplied through ta fluid inlet 24e. A passageway 26e places the accumulator 22e in fluid communication with the channel exit 32e, a chamber 48e and the throat 66e of a resonator 60e. A shim 40e maintains a nozzle block 38e in position downstream of the channel exit 32e. The nozzle block 38e includes a boundary 4de having a portion 42e lying adjacent a jet stream 43e. A bleed passageway 124, which is controlled by a valve 126, is provided in the plate 14e for the leakage of fluid into the separating means or chamber 48e. The purpose of this iiuid passageway and valve, is to allow ne control for the adjustment of the stream at its monostable Voperating promt.

A second nozzle block Sfe is mounted downstream of both the channel exit 32e and the portion 42e and includes a boundary 54e having a portion 52e laterally adjacent jet 43e. A suitable wedge 12% is positioned downstream of the channel exit 32e to direct the ilow tI-3e along the Iboundary 44e. The stability of the stream 43e operating in the monostable region is controlled by the valve 126. Increasing 4the low resistance of the leak through the passageway 121tis equivalent to changing the inclination angle of the boundary 44e or changing the distance from the boundary 44e to the centerline of channel 26. Thus, the leakage of uid through the passageway 124 is etectively a low pass lter and does not iniluence the acoustical properties of the system. The stream 43e can be switched from the boundary 4de to the boundary 54e by a sound 72 in the same manner as described in connection with the FIGURE 1 embodiment.

Referring now to FIGURES l0 and l1, a seventh embodiment of the present invention, generally designated lltf, includes a 'housing 13@ having a partially encompassing sidewall 132, first and second endwalls 134 and 136 and a pair of spaced, parallel interior partitions 13d and 14A?. The endwall 13o and the interior partition form a fan chamber 142 in which a blower 144 is rotatably mounted. Upon rotation by a motor 145, the blower 9 144 draws air in through an opening 146 provided in the endwall 136. The blower 144 discharges into a duct 14S- which conveys the air to a passageway 216]c communicating with the channel exit 321. The duct 14S is also in communication with an acoustical filter chamber 149 through an aperture 151) provi-ded in the partition 138.

The endwall 134- and the partition 138 dene a compart4 ment 152 in which the channel exit 32f, a iirst nozzle blocking member 958]c and a second blocking member 50f are mounted. The sidewalls 134 and 138 as well as housing 131) form a `resonator chamber 60j.

The nozzle block 38]c includes the usual boundary wall 44j having a portion 427 laterally adjacent a jet stream 43f issuing from the channel exit 32f. Also, the nozzle block Sif includes a boundary 54] having a portion 52f laterally adjacent the jet stream 43f and lying downstream of the portion 42]. A plate member 156 is also mounted in the chamber 152 to form a separation means or chamber 43] between the channel exit 321 and the porti-on 421C.

The device f may be used to control the `operation of a suitable mechanical device, such as the vane means 158 which is pivotally mounted on the partition 138 by a pin 169 and a supporting member 162. The vane means 158 includes semi-cylindrical portions 164 and 165 which extend over the boundaries 44] and 54], respectively', in the path of flow of the fluid 431i when it is attached to the respective boundaries 44]c and 54j. The vane means 1.58 is statically and dynamically balanced and may be rocked in a counterl clockwise direction, Ias viewed in FIGURE 10, by stream 43]c when it is attached to the boundary Erl-f. The vane means is rocked in a clockwise direction by stream 43f when it is attached to boundary 44f. Thus, the vane means 15d can be caused to teeter back and forth on support 162 by subjecting stream 431 to a sound 72]' cyclically.

The embodiments of the present invention shown in FIGURES 12 and 13 illustrate that single blower may be advantageously used to supply duid to a plurality of channels having a number of different locations.

The device shown in FIGURE 12, generally designated 10g, includes a housing 17@ having endwalls 172 and sidewalls 174. A blower chamber 176 is provided in the housing 171). A blower 178 is rotatably mounted in the blower chamber 176 for supplying a suitable fluid, such as air or water, under pressure to a Iirst channel 26g provided in the rear portion of housing 1711 and a second channel 2611 provided in the front portion thereof. The air eXits from channel 26g through the channel exit 32g and from channel 26h through the channel exit 32h. A blocking member 311g is mounted in housing 17] downstream of the nozzle 32g and includes a boundary wall 44g having a portion 42g laterally adjacent a jet stream 43g which issues from channel exit 32g when blower 173 is energized. A separation means or chamber 48g and a resonant chamber 611g are also provided in the rear portion of housingy 170.

Energization of blower 173 also causes a jet stream 43h to exit from channel exit 32h and attach to the boundary wall 141/1 of a nozzle block 38h having a laterally adjacent portion 42h located downstream of channel exit 3211 in the front portion of housing 171i. A resonant chamber 61th, a separation `means 48h and a nozzle block 51111 are also provided in the front portion of the housing 171?. A sound 72h, which drives the chamber 611171 into resonance, may then be employed to switch the stream 43h from boundary wall 4411 to a boundary wall 5411 on block 51111 having a laterally adjacent portion 52h. The chambers 611g and @t1/1 may be tuned to different frequencies if desired. The jet streams 43g and 43h may be switched to perform various work functions. While many uses for the device 111g will manifest themselves, it may be advantageously used to propel and control the direction of movement of a ground effect vehicle.

Referring now to FIGURE 13, a uid dynamic control device, generally designated 11111, includes a housing 134 having sidewalls 135 between which a iirst resonant charnber 601' and a second resonant chamber 60j are provided. A blower chamber 186 is also provided in the housing 184 in which a fan or blower 153 is rotatably mounted. Upon energization, the blower 133 simultaneously supplies air under pressure to a first channel 261' and a second channel 26] which are also provided in the housing 184. Air leaves the channels 261' and 26]' through channel exits 321' and 32]' respectively, and attaches to the boundary walls 441' and 44]' of nozzle blocks 381' and 38]', respectively. The nozzle blocks 381' and 38]' have laterally adjacent portions 421' and 42]', respectively, which are located downstream of their associated channel exits. The nozzle blocks 381' and 38]' include suitable separating means 481' and 48j, respectively, and a passageway 191) is provided in the nozzle block 381 to provide a biasing means for controlling the pressure in chamber 481'.

A first sound 721' having a frequency which drives the chamber 6111' into resonance may be used to switch the rst stream 431' from the nozzle block 381' to a nozzle block 501 having a boundary wall 541' and a laterally adjacent portion 521' which is located downstream of the portion 421'. A second sound 72]', which may have a different frequency than the sound 721', if desired, and which drives resonant chamber 66] into Iresonance, may be employed to switch a second stream 43]' from the bloc-k 38]' to a nozzle block 50]' having a boundary wall 54]' and a later-ally adjacent por tion 52]' which lies downstream of the portion 42]'. It is to be noted that when the stream 431' is attached to nozzle block 381' and the stream 43]' is attached to nozzle block 59]', right angle forces will be applied to housing 1S4.

Referring now to FIGURE 14, a uid eontnol device 10k includes la uid supply chamber 22k, a channel 26k, a channel exit 312k, a separating means 48k and a reso! nator 60k. The device 10k may be employed as a thrust vectoring device having a set line of thrust T1 created lby a jet stream 43k which may be switched acoustically to a set line of thrust T2 for ight control.

It is known that thnust produced by a jet is not solely a matter of pushing on a surface or material against which the jet is directed. An essential feature of thrust is that it yarises from 1a mass displacement of the material being forced out by the jet-regardless of any medium, or lack of it, into which or against which the jet is being forced. Thus, the thrust derived from the expulsion of mass by the jet 43k may be considered as providing a force and an associated couple applied at the center of mass cm of the device 10k. By changing the line of action of the thrust vector T1 acoustically from the boundary 38k to the boundary 511k in the manner described in connection with the FIGURE 1 'embodiment of the present invention, the magnitude of the force remains unchanged, b:ut its direction and the magnitude of the couple change. Hence, flight conti'ol of the device 111k is obtained.

Another example of flight control is illustrated in FIGURE 15 wherein a iluid control device ltlL includes a center of mass cm, a fluid supply chamber 2.2L, a plurality of channels 26L, 26m and 2611 and separating means 48m and 4811. Three fixed lines of thrust TL, Tm and Tn are established by jet streams 4311.., 43m and 4311 which emanate from the fluid supply chamber 22L. The jet stre-ams 43m yand 4311 are normally attaohed to the boundaries 33m and 3811, respectively, along which they flow to a common point of discharge with the jet stream 431, to create a thrust vector TL through the center of -mass cm. The device 1111, also includes a rst resonator 60m which may be driven into resonance acoustically to switch the jet stream 43m to the boundary 50m causing the line of thnust TIn to create -a rst couple which is applied at the center of mass cm. The device IOL also includes a second resonator 6011 which may be driven into resonance acoustically to switch the jet stream 431/1 from the boundary 3%11 to the boundary 5011 causing the lin'e of thrust Tn to create a second couple which is applied at the center of mass cm. Thus, the

device L provides a device which has three fixed lines of thrust and which operates substantially the same as the previously described devices.

Yet another example of flight control is illustrated in FIGURES 16 and 17 wh'erein an air cushion vehicle 10o includes Ia power plant 13o for supplying a curtain jet 430 which discharges through a peripheral nozzle 32o around the circumference of the vehicle 1190. The vehicle 10o also includes resonators 6Go and 60p, boundaries Silo and 50p, separating means 480 and 48p and boundaries 330 and 38p. The curtain jet 430 which is directed against a relatively solid surface to support the vehicle 100 thereabov'e may be altered -acoustically to create low pressure and 'high pressure areas as the jet is deliected from the surface S to effect a thrust in a particular direction. The curtain jet 43o is normally attached to boundaries 50o and 59p. When resonator 600 is driven into resonance, a segment of the jet 43o switches to the boundary 380 removing this segment of the jet from surace S, thereby creating a low-pressure area in the vicinity of the removed segment. This gives the vehicle 10o a thrust component in the direction of the llow-pressure tarea. Wh'en the resonator oop is driven into resonance, another segment of -the jet 430 is removed from the surface S giving the vehicle lilo a thrust component in another direction.

While the particular fluid dynamic control devi-ces herein shown `and described in detail are fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that they yare merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

What is claim'ed is:

1. A fluid dynamic controlled device, comprising:

liuid-stream-forming means for forming a stream or fluid;

first boundary means laterally adjacent one side of said stream;

Vsecond boundary means laterally adjacent the other side of said stream, said second boundary means Ibeing generally 'opposite and downstream of said first boundary means;

separating means adjacent to and upstream of said first boundary means for creating `a pressure -gradient across said stream in a direction to deflect it onto said first boundary means; and

vibratory means for directing a vibratory flow of fluid at said stream adjacent said separating means to disturb said stream in such la manner that the pressure adjacent said second boundary means is reduc'ed whereby the `direction yof said pressure gradient is reversed across said stream to switch said stream from said first boundary means to said second boundary means.

2. A device as defined in claim 1 wherein said stream returns to said first boundary means when said vibratory flow of fluid is removed.

3. A device tas defined in claim 1 including vane means downstream of said boundary means in the path of liow of said stream when it is flowing along one of said boundtary means for actuation thereby.

4. A device yas defined in claim 1 wherein said streamforming means includes channel means having substantially parallel spaced sidewalls for producing la plane stream with an aspect ratio greater than 5 to l.

5. A device as defined in claim 1 including resonator means in communication with said stream generally opposite said separating means, said resonator means being driven into resonance by said vibratory m'eans.

6. A device as defined in claim 4 wherein said streamforming means includes an accumulator in fluid communication with said channel means for supplying fluid thereto to produce said stream.

7. A device as defined in claim 5 wherein said separating means comprises a second resonator means.

8. A device as defined in claim 1 including bleed passageway means in liuid communication with said separating means.

9. A device as defined in claim 1 including wedge means positioned between said boundary means for directing said stream along said boundary means.

1li. A device as defined in claim 9 including means forming a power jet adjacent said wedge m'eans, said power jet being held off said wedge means by said iiuid stream when itis flowing along said first boundary means, said wedge means including third boundary means along which said power jet flows when said fluid stream is switched from said first boundary means to said second boundary means.

11. A device las defined in claim 3 wherein said vane means is mounted in the path of iiow of said fluid stream for actuation thereby when said liuid stream is flowing along either of said boundary means.

12. A fiuid `dynamic device, comprising:

housing means;

ian accumulator chamber provided in said housing means for storing a fluid under pressure therein;

conduit means connecting said accumulator chamber to a source of fluid under pressure;

channel means in fluid communication with said accumulator chamber, said channel means including substantially parallel, spaced sidewalls, the end of said channel means which is remote from said accumulator chamber forming an exit orifice, the depth of said channel being approximately ten times its width and the length of said channel being approximately 20 times its width, whereby a laminar flow is imparted to said fluid leaving said accumulator chamber before it reaches said exit orifice, said fluid leaving said orifice in a plane stream, the aspect ratio of said plane stream Ibeing greater than 5 to 1;

first boundary means mounted in said housing downstream of said eXit orifice, said first boundary means including -a first laterally adjacent portion which lies laterally adjacent one side of said stream and an oblique face connecting said first laterally adjacent por-tion to a downstream portion of said first bound- 'ary means;

spacer means mounted in said housing between first 'boundary means and said yexit orifice for forming a separating chamber .between said first laterally adjacent portion and said exit orifice for creating a pressure gradient across said stream in a lirst direction, whereby Isaid stream attaches to said first boundary means;

second boundary means mounted in said housing, said second boundary means including a second laterally adjacent portion lwhich lies laterally adjacent the other side of said stream downstream of said first laterally adjacent portion, said second boundary means also including `an oblique face connecting said second laterally adjacent portion to a downstream portion;

a resonator mounted in said housing in fluid communication with said separating chamber between said sennd laterally adjacent portion and said eXit orifice; an

sound means for driving said resonator into resonance to disturb said stream in such a manner that the ambient pressure adjacent said second boundary means is reduced whereby the direction of said pressure gradient is reversed across said stream to switch said stream from sai-d first boundary means to said second boundary means.

13. A device as defined in claim 12 wherein said stream returns to said first yboundary means when the disturbance created by said sound means is removed.

13 14. A device as defined in claim 12 wherein said second boundary means lies upstream of said first boundary means.

15. A device as defined in claim 12 wherein said sepiaratin-g chamber comprises a resonator chamber.

16. A device las defined in claim 12 including Wedge means .mounted in said housing intermediate said first and `second boundary means downstream of said first and second laterally adjacent portions for directing said stream along said boundary means.

17. A device as defined in claim 16 inclu-ding means forming a power jet adjacent said wed-ge means, said power jet being held E of said wedge means by said stream when it is flowing lalong said first boundary means, said wedge means including third boundary means along which sai-d power jet flows when said stream is switched from said -first boundary means to said second boundary means.

18. A ldevice as defined in claim 17 wherein said stream returns to said first boundary means when the disturbance created by said sound means is removed.

19. A device as defined in claim 17 including blower means mounted `in said housing means for supplying fluid to said accumulator and for forming said power jet.

20. A fluid dynamic control device comprising: a housing; la blower rotatably mounted in said housing; channel means provided in said housing in fi-uid communication with said blower, said channel means including a discharge end forming exit -orifice means, said blower supplying a fluid under pressure to said exit orifice means when energized, said channel Imeans and said exit orifice means being adapted to conve-rt the fluid fiow from said blower into a plane stream having :a laminar flow; first boundary means mounted in said housing downstream of said exit orifice means, said first boundary means including a laterally adjacent portion lying laterally adjacent one side of said stream;

separating means mounted in said housing adjacent to and upstream of said first boundary means for creating a pressure `gradient across said stream in a -direction to deliect it on to said yfirst boundary means;

second boundary means mounted in said housing downstream of said first laterally adjacent portion, said second boundary means having a second laterally adjacent portion which lies laterally adjacent the other side of the said stream;

resonator means mounted in said housing in fluid cornmunication with Isaid separating means between said second laterally adjacent portion `and said exi-t orifice means; and

sound means for creating a sound distunbance to drive sai-d resonator means into resonance to disturb said stream in such a manner that the ambient pressure adjacent sai-d second boundary means is yreduced whereby the direction of said pressure gradient is reversed across said stream to switch said stream from said first boundary means to said second boundary means.

21. A device as defined in claim 20l wherein said stream returns to said first boundary means when said disturbance is removed.

22. A device as defined in claim 20 including vane means mounted in said housing downstream of said boundary means in the path of flow of said stream when it is flowing along one of said boundary means for actuation thereby.

23. A device as defined in claim 22 wherein said vane means is mounted in the path of flow of said fluid stream for actuation thereby when said fluid stream is flowing along either of said boundary means.

24. A device as defined in claim 22 including electrical contact means connected to said vane means for actuation thereby.

25. A device as defined in claim 2d including acoustical filter means mounted in said housing in communication with said channel means for attenuating the sound from said blower in a frequency band near the resonant frequency of said resonator means.

26. Apparatus for controlling the direction of movement of -a vehicle, comprising:

a housing;

blower means rotatably mounted in said housing means for generating a fluid stream; first fluid stream forming means provided in said housing in communication with said blower means for forming a first plane stream having a laminar flow;

first boundary means mounted. in said housing downstream of said fluid stream forming means laterally adjacent one side of said first plane stream;

second boundary means mounted in said housing laterally adjacent the other side of said first plane stream, said second boundary means being generally `opposite and downstream of said first boundary means;

first separating means mounted in said housing adjacent to and upstream `of said first boundary means for creating a first pressure gradient across said first stream in a direction to deflect it onto said first boundary means, said first plane stream traveling along said first boundary means and exiting from said housing into ambient atmosphere, whereby said first -plane stream exerts thrust against said housing means from a first direction when .it is in position on said first boundary means;

first vibratory means for directing a vibratory flow of fluid at said first plane stream adjacent said first separating means for creating a first disturbance to distu-rb said first stream in such a manner that the ambient pressure adjacent said second boundary means is reduced whereby the direction of said first pressure gradient is reversed across said first stream to switch said first stream from said first boundary means to said second boundary means, whereby said first plane stream exits from said housing into `the atmosphere and exerts thrust against said housing in a second direction when it is fiowing along said second boundary means;

second fiuid stream forming means provided in said housing in communication with said blower means for forming a second plane stream having a laminar flow;

third boundary means mounted in said housing means laterally adjacent one side of said second plane stre-am;

fourth boundary means mounted in said housing means laterally adjacent the other side of said second plane stream, said fourth boundary means being generally opposite and downstream of said third boundary means, whereby said second plane stream discharges between said boundary means into the ambient atmosphere outside said housing;

second separating means mounted in said housing adjacent to and upstream of said third boundary means for creating a second pressure gradient across said second plane stream in a direction to deliect it onto said third boundary means; and

second vibratory means for directing a vibratory fiow of fluid at said second plane stream adjacent said second separating means for creating a second disturbance to disturb said second stream in such a manner that the ambient pressure adjacent said fourth boundary means is reduced whereby the direction of said second pressure gradient is reversed across said sec- -ond plane stream to switch said second plane stream from said -third boundary means to said fourth boundary means, said second plane stream exerting thrust against said housing means in a third direction when it is flowing along said third boundary means, said lf3 second plane stream exerting thrust against said housing means along a fourth direction when it is fiowing along said fourth boundary means.

27. An apparatus as defined in claim 26 wherein said first and second streams return to said first and third boundary means, respectively, when said first and second disturbances, respectively, are removed.

28. An apparatus `as defined in claim 26 including first resonator means in communication with said first stream and generally opposite said first separating means, said first resonator being driven into resonance by said first vibratory Ine-ans;

and including second resonator means in communication with said second stream and generally opposite said second separating means, said second resonator being driven into resonance by said second vibratory means; said first and second vibratory means having different frequencies.

29. An apparatus defined in claim 26 wherein said first plane stream discharges from one end of said housing and said second plane stream discharges from another end thereof.

30. An apparatus as defined in claim 26 wherein the force which is exerted on said housing by said first and second plane streams lies substantially at right angles to each other when said plane streams are flowing along predetermined boundary means.

31. A thrust vectoring device for controlling the direction of movement of a ve-hicle, comprising:

a housing means;

power jet supply means provided in said housing means for supplying a power jet to impart thrust to said device, said power jet supply means including a first exit nozzle;

first boundary means mounted in said housing means laterally adjacent said power jet downstream of said first exit nozzle;

control jet supply means provided in said housing means for supplying a control jet to control said power jet, said control jet supplying means including a second exit nozzle;

second boundary means mounted in said housing means laterally adjacent one side of said control jet down stream of said second exit nozzle for directing said control jet into the path f flow of said power jet when said control jet is attached to said second boundary means, said second boundary means being mounted in said housing means between said power jet and said first boundary means;

separating means provided in said housing means between said secondary boundary means and said second nozzle for normally maintaining said control jet attached to said second boundary means, whereby said control jet maintains said power jet out of engagement with said first boundary means;

third boundary means mounted in said housing means laterally adjacent the other side of said control jet downstream of said second nozzle; and

vibratory means for creating a disturbance by directing a vibratory flow of fluid at said control jet to disturb said control jet so that it switches from said second boundary means to said third boundary means, whereby said power jet becomes attached to said first boundary means to change the direction of thrust imparted to said device by said power jet.

32. A device as defined in claim lill wherein said con* trol jet returns to said second boundary means when said disturbance is removed.

33. A device as defined in claim 31 wherein said vibratory means includes a resonator mounted in said housing in communication with said separating means, said second boundary means and said third boundary means.

34. In combination with a device deriving thrust from the expulsion of mass by a jet stream providing a force and an associated couple applied at the center of mass of l@ said device along a first line of action, thrust vectoring means comprising:

boundary means laterally adjacent said jet stream for defining a second line of action, whereby the direction and magnitude of said couple may be changed by causing said jet stream to switch from said first line of action to said second lline of action; and means for switching said jet stream from said first line of action to said boundary means, said switching means including:

separating means adjacent to and upstream of said boundary means for creating a pressure gradient across said jet stream in a direction to defiect it away from said boundary means; and vibratory means for directing a vibratory flow of fluid at said jet stream adjacent said separating means to disturb said jet stream in such a manner that the pressure adjacent said boundary means is reduced, whereby the direction of said pressure gradient is reversed across said jet stream to switch said jet stream from said first line of action to said second line of action along said boundary means.

35. A combination as defined in claim 34 wherein said jet stream returns to said first line of action when said vibratory flow of fluid is removed.

36. A combination as defined in claim 34 wherein said switching means also includes resonator means in communication with said jet stream generally opposite said separating means, said resonator means being driven into resonance by said vibratory means.

37. In combination with a device deriving thrust from the expulsion of mass by a first jet stream discharging from said device along a first set -line of action through the center of mass of said device, thrust vectoring means, comprising:

first fluid-stream forming means for forming a second jet stream; first boundary means laterally adjacent one side of said second jet stream, said first boundary means defining a second set line of action through said center of mass when said second jet stream is attached thereto;

second boundary means laterally adjacent the other side of said second jet stream, said second boundary means being generally opposite and downstream of said first boundary means for directing said second jet stream into the path of flow of said first jet stream when said second jet stream is attached to said second boundary means;

first separating means adjacent to and upstream of said first boundary means for creating a first pressure gradient across said second jet stream in a direction to deflect it onto said first boundary means;

first vibratory means for directing a first vibratory flow of fiuid at said second jet stream adjacent said first separating means to disturb said second jet stream in such a manner that the pressure adjacent said second boundary means is reduced whereby the direction of said first pressure gradient is reversed across said second jet stream to switch it from said first boundary means to said second boundary means, whereby said second line of action is established through said center of mass;

second fluid-stream-forming means for forming a third jet stream;

third boundary means laterally adjacent one side of said third jet stream, said third boundary means defining a third set line of action through said center of mass when said third jet stream is attached thereto; fourth boundary means laterally adjacent the other side of said third jet stream, said fourth boundary means being generally opposite and downstream of said third boundary means for directing said third jet stream into the path of fiow of said first jet stream l17 when said third jet stream is attached to said fourth boundary means; second separating means adjacent to and upstream of said third boundary means for creating a second pressure gradient across said third jet stream in a direction to deflect it onto said third boundary means; and

second vibratory means for directing a second vibratory flow of fluid of said third jet stream adjacent said second separating means to disturb said third jet stream in such a manner that the pressure adjacent said fourth boundary means is reduced whereby the direction of said second pressure gradient is reversed across said third jet stream to switch it from said third boundary means to said fourth boundary means, whereby said third line of action is established through said center of mass.

38. A combination as defined in claim 37 wherein said second jet stream returns to said first boundary means when said rst vibratory flow of uid is removed and wherein said third jet stream returns to said third boundary means when said second vibratory flow of fluid is removed.

39. A combination as defined in claim 37 including first resonator means in communication with said second jet stream generally opposite said first separating means, said first resonator means being driven into resonance by said first vibratory means and second resonator means in communication with said third jet stream generally opposite said second separating means, said second resonator means being driven into resonance by said second vibratory means.

40. A combination as defined in claim 37 wherein said first and second separating means comprise first and second resonator means, respectively.

41. In combination with an air cushion vehicle having a curtain jet discharging through peripheral nozzle means around the circumference of said vehicle for deflection from a surface to effect a thrust in a predetermined direction, ight control means comprising:

boundary means laterally adjacent a predetermined portion of said curtain jet for deflecting said predetermined portion of said curtain jet away from said surface when said predetermined portion is attached to said boundary means, whereby a low pressure area is created on said surface to effect a thrust in a second predetermined direction; and means for switching said predetermined portion of said curtain jet from said surface onto said boundary means, said switching means including:

separating means adjacent to and upstream of said boundary means for creating a pressure gradient across said predetermined portion of said curtain jet in a direction to deflect it away from said boundary means and onto said surface; and

vibratory means for directing a. vibratory ow of fluid at said predetermined portion of said curtain jet adjacent said separating means to disturb said pretermined portion in such a manner that the pressure adjacent said boundary means is reduced, whereby the direction of said pressure gradient is reversed across said predetermined portion to switch it from said surface to said boundary means.

42. A combination as defined in claim 41 wherein said predetermined portion of said curtain jet returns to being deflected from said surface when said vibratory flow is removed.

43. A combination as defined in claim 41 wherein said switching means also includes resonator means in communication with said predetermined portion of said curtain jet generally opposite said :separating means, said resonator means being driven into resonance by said vibratory means.

44. An air cushion vehicle adapted to be supported above a suitable surface comprising:

peripheral nozzle means encompassing said vehicle body member for forming a curtain jet passageway in communication with said surface;

power supply means in communication with said peripheral nozzle means for forming said curtain jet and directing it through said passageway onto said surface;

boundary means mounted in said body member laterally adjacent a segment of said curtain jet for deflecting said segment away from said surface when said segment is attached to said boundary means, whereby a low pressure area is created on said surface; and separating means adjacent to and upstream of said boundary means for creating a pressure gradient across said predetermined. portion of said curtain jet in a direction to defiect it away from said boundary means and onto said surface; and

vibratory means for directing a vibratory flow of fluid at said segment adjacent said separating means to disturb said segment in such a manner that the pressure adjacent said boundary means is reduced, whereby the direction of said pressure gradient is reversed across said segment to switch it from said surface to said boundary means.

References Cited by the Examiner UNITED STATES PATENTS MARK NEWMAN, Primary Examiner. C. R. CR-OYLE, Assistant Examiner. 

1. A FLUID DYNAMIC CONTROLLED DEVICE, COMPRISING: FLUID-STREAM-FORMING MEANS FOR FORMING A STREAM OF FLUID; FIRST BOUNDARY MEANS LATERALLY ADJACENT ONE SIDE OF SAID STREAM; SECOND BOUNDARY MEANS LATERALLY ADJACENT THE OTHER SIDE OF SAID STREAM, SAID SECOND BOUNDARY MEANS BEING GENERALLY OPPOSITE AND DOWNSTREAM OF SAID FIRST BOUNDARY MEANS; SEPARATING MEANS ADJACENT TO AND UPSTREAM OF SAID FIRST BOUNDARY MEANS FOR CREATING A PRESSURE GRADIENT ACROSS SAID STREAM IN A DIRECTION TO DEFLECT IT ONTO SAID FIRST BOUNDARY MEANS; AND VIBRATORY MEANS FOR DIRECTING A VIBRATORY FLOW OF FLUID AT SAID STREAM ADJACENT SAID SEPARATING MEANS TO DISTURB SAID STREAM IN SUCH A MANNER THAT THE PRESSURE ADJACENT SAID SECOND BOUNDARY MEANS IS REDUCED WHEREBY THE DIRECTION OF SAID PRESSURE GRADIENT IS REVERSED ACROSS SAID STREAM TO SWITCH SAID STREAM FROM SAID FIRST BOUNDARY MEANS TO SAID SECOND BOUNDARY MEANS. 